One way valve is a hydraulic control valve in the direction of the system, its main role is to limit the oil can only flow in one direction, can not flow in the opposite direction. Check valve structure and working principle are relatively simple, but it is one of the most widely used in the hydraulic system components, rational choice and application of one-way valve can not only meet the different applications of the various functions of the hydraulic system, but also can simplify the design of hydraulic system. This paper introduces the typical application of one-way valve in the actual hydraulic system and the matters needing attention.
Classification and characteristics of 1 check valves

One way valve according to the different characteristics of its structure, generally divided into ordinary one-way valve and hydraulic control valve two categories. Ordinary one-way valve symbols shown in Figure 1a, its function is to only allow the oil to flow in one direction (from A to B), and does not allow the reverse (from B to A) flow; hydraulic control valve of graphic symbols in Figure 1A shown, its function is to allow oil in a direction of flow (from A to B), while the reverse flow (from B to A) must be controlled by oil (C) to achieve.

The performance requirements of one-way valve are: when the oil flow through the check valve resistance to be small, that is the pressure loss is small; and when the reverse flow of oil, the valve sealing better, no leakage; work should not have vibration, shock and noise.

2 one-way valve application

1) protection of hydraulic pump

As shown in Figure 1b, one-way valve 3 installed in the hydraulic pump outlet of the 1, to prevent the sudden rise of the system pressure (such as accumulator, such as the release of the pressure of 4) to the hydraulic pump, to avoid reverse or damage to the pump, the role of the protection of hydraulic pump.

2) to prevent interference

Double pump oil supply system as shown in Figure 1C, when the system pressure is low, and the output of the 2 pump 1 pump oil confluence of common oil to the system, to meet the needs of large flow system; when the system pressure is higher than the set pressure relief valve 5, 2 low pressure pump unloading, only 1 high-pressure pump oil to the system at this time, separated by a one-way valve 4, the high-pressure oil and low pressure oil, do not affect each other.